Sentences with phrase «carbon isotopic ratio»

Note that ppm and delta13C are not the same at all altitudes and evolve progressively, as illustrated by the airborne measurements of Nakazawa et al., Time and space variations of the carbon isotopic ratio, Tellus, 1993.

In other words, if all of the terrestrial carbon today (in forests, animals, soils, etc.) were converted to carbon dioxide and returned to the global inorganic carbon pool, the change in the global carbon isotopic ratio would only be a third as big as that observed during the PETM!

In collaboration with the Institute for Arctic and Alpine Research (INSTAAR) of the University of Colorado, ESRL / GMD now routinely monitors carbon isotopic ratios of CO2 and CH4.

Not exact matches

By comparing the isotopic ratios of nitrogen and carbon in the lions» remains with that of contemporary lions, humans and herbivore prey, Justin Yeakel of the University of California, Santa Cruz, estimates the lions ate around 35 people.

By comparing the isotopic ratios of nitrogen and carbon in the lions» remains with that of contemporary lions, humans and herbivore...

As a result, methane emissions have distinct isotopic values: Methane emitted from any microbially driven source such as wetlands or agriculture have values of about -60 ‰ (signifying a relatively low ratio of carbon - 13 to carbon - 12); oil, gas, and coal emissions have an average carbon isotopic value of -37 ‰; and tree and crop burning averages about -22 ‰.

Animals that live in the sea have ratios of carbon and nitrogen isotopes that differ from those found in terrestrial animals, and this isotopic signature is passed on to the people who eat them.

Because the isotopic ratios of carbon and hydrogen display geographic variation, the composition of a feather can reveal where the bird was when the feather grew.

One of Mojzsis's former coauthors, geochemist Gustaf Arrhenius of the Scripps Institution of Oceanography, showed how the Isua carbon - isotopic ratio could arise by geologic activity alone, if certain iron minerals in the rock were melted and pressed together over time.

The information about oxygen concentration comes from the isotopic composition of carbon or rather from the ratio between the stable carbon isotopes 12C and 13C.

Initial SAM results show an increase of 5 percent in heavier isotopes of carbon in the atmospheric carbon dioxide compared to estimates of the isotopic ratios present when Mars formed.

Next, the methane in this air is combusted to produce carbon dioxide, which is analysed for its carbon isotopic composition — or carbon - 13 to carbon - 12 ratio.

Its isotopic signature is depleted in the carbon - 13 isotope, which explains why the atmospheric ratio of carbon - 12 to carbon - 13 has been going down as anthropogenic carbon dioxide goes up.

«THE stable carbon isotopic (13C / 12C) record of twentieth - century tree rings has been examined1 - 3 for evidence of the effects of the input of isotopically lighter fossil fuel CO2 (δ 13C ~ -25 ‰ relative to the primary PDB standard4), since the onset of major fossil fuel combustion during the mid-nineteenth century, on the 13C / 12C ratio of atmospheric CO2 (δ 13C ~ -7 ‰), which is assimilated by trees by photosynthesis.

Curiously, the PETM was accompanied by an exceptionally large change to the global carbon cycle as indicated by a large drop in the isotopic ratio of 13C to 12C in the ocean and on land.

If he wanted to apply his scientific credentials to a scientific matter in climate, he might turn to what the isotopic ratio of carbon (13C / 12C) needs to be in atmospheric CO2 concentration to constitute a fingerprint of human origin.

«Measurement of atmospheric mixing ratios, decline of O2 mixing ratios, pCO2 in the ocean, and the isotopic carbon composition and other stuff tells us about the source of CO2 increases.

Which is ludicrous in the context of CO2, since we can measure isotopic ratio changes (indicating the change in old carbon versus fresh carbon) and have good accounting for human inputs to the system versus sources and sinks.

Looking at the isotopic record from the PETM, scientists see both carbon and oxygen isotope ratios spiking in exactly the way we expect to see in the Anthropocene record.

The researchers were able to discern agricultural methane from other sources of methane by looking at the gas» isotopic signatures — or the ratio of various carbon isotopes — using data from atmospheric monitoring stations around the world.